Figure 4. Thickness of films produced using soap-film coating.

(a) Schematic drawing of the coating of a monolayer at high-speed and (b) a multilayer at a lower speed. (c) Thickness of a film of silica nanoparticles as a function of deposition speed (log–log diagram) for two different concentrations of nanoparticles - 11 wt% (square) and 14 wt% (circular). The measurements were performed using the SFC method; however, similar behaviours were observed using the bSFC method. (d) Optical absorption, which is proportional to the thickness, of methyl blue films produced using SFC. The dashed lines in (c) and (d) are least-squares fits to the data and indicate a thickness dependency of approximately ~U^−0.7, where U is the speed of the substrate through the soap film.